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600 lbs of TQ possible ??

I'd be shooting for somewhere between 450-500 then.

440 is already attained by the military 6.5's. Tweaking it up 50 odd lb/ft from that number is probably attainable while maintaining reliabilty/manners.

I do believe we're beginning to "cuddle up" to the lb/ft limitations of the stock 4L80E around those numbers also.....
 
If your looking for 600foot lbs to the wheels, then I would say streetable is out of the question. that would put you way over 700 at the engine which would be awfully hard to do with an IDI engine. Even guys with the early DURAMAX have to put quite a bit of fuel to em to get 600 at the wheels. Even 600 at the flywheel would be pushing the daiy driving threshhold I think. Indirect injected engines are just not as efficient at making huge torque numbers, they are very good at making good milage and reasoneable power levels though. I knoiw several are pushing the envelope with the 6.5, but most all of them are using the new style NAVISTAR blocks to hold up to it.
 
I do have a Navistar Optimizer engine and many mods to go along with it. I was aware of the military 440 tq rating too, but was thinking with all the mods I have that I should be able to surpass the 440 mark with ease and better then 50 lbs.

I also think that the Transgo HD-2 kit really increases the torque capacity of the 80e.. seems like I took a peek at the instructions for the last one I had done.

I guess time will tell and so will a dyno..
 
great white said:
Iirc, limiting factor on the 4L80e is the input shaft itself....
Click to expand...


The input shaft on 91-early 99's was a limiting factor as far as engine braking went, but they really didn't limit there HP holding ability.The TRANSGO HD2 kit does help out alot, but the main limiting factor with them is weight and 4th gear. In a lightweight application the 4L80E can hold over 1000 foot pounds of torque as evidenced by the DURAMAX MUSTANG of Mike Woods from NX Express. He has dynod over 1200HP to the wheels and the torque was almost 2K foot pounds. He is running a 4L80E trans, but keep in mind he is only about 3400 pounds as well. A 7K pound truck should be careful with a 4L80E in OD. If it wasn't for the 4L80E's OD unit, the DURAFLITE trans would have never had been built as the 4L80E could have done the job.
 
There ya go.

I did know the 4L80E has been built to handle far more than our trucks make.

I guess I must have had the castrated duramax/4L80e van combo and the drilled input shaft in the back of my mind...
 
Great info Guys !!!

I do have another 4L80e just sitting that the front pump was out of.. it was a gm goodwrench trans, so I'm not sure of the year of it. I really love the 4L80e / 85e trans soo much as I am still considering the low ow first gear set for it.. 3:1 first gear, cant remember the second gear, but get's it closer to the 700r ratio's.. I love em and think that it would be beneficial for towing.

As for as the OD being an issue... I don't do anything real crazy with my vehicles to have that as a problem. I do, in the future want to get a 5th wheel and go to Alaska for a summer though.

What is the Duraflite trans ??
 
THEFERMANATOR said:
If it wasn't for the 4L80E's OD unit, the DURAFLITE trans would have never had been built as the 4L80E could have done the job.
Click to expand...

Overdrives are generally a weak spot and waste a little HP as they are a gear set. What ya want is as many speeds as you can stuff in and a 1 to 1 top gear so the power flow is straight through, one direct clutch, and adjust the cruise RPM with the diff gears. But the bean counters wanted to do a running change and the marketing dufuses wanted to advertise an overdrive to the dumbmasses. ;)

I have a Jag with a Chevy V8/700r4 and a good 6.2 TH700r4 pair in RustBucket. Very tempting, that show car gave me ideas (not really :hihi: )
 
great white said:
There ya go.

I did know the 4L80E has been built to handle far more than our trucks make.

I guess I must have had the castrated duramax/4L80e van combo and the drilled input shaft in the back of my mind...
Click to expand...

The DURAMAX/4L80E combo got the solid input shaft as GM changed them mid year 99 when they upgraded the 4L80E drastically. Gm rates the later 4L80E's at 450 foot pounds of torque IIRC, but early models were only rated at 390 or so. It is a good trans without a doubt, but the OD unit is a weak spot as teh 4L80E is nothing more than a turbo 400 with a gear vendors built into it basically.
 
Gotta spend some $ to do it. ~ $10k.

18-19.5 C/R engine, Modified Holset, Intercooler, Kennedy Tune, Intake & Exhaust, Marine Nozzles. ~320HP ~600TQ, but you're done, it's maxed out.
 
I think I have at least what is needed to produce in excess of 300 rear wheel hp without a "tune" of any sort.. I just want gobs of TQ without going to a Cummins.
 
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